1 files changed, 7 insertions, 3 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index d2b6d44962b7..ad6e4eaf34f8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -36,6 +36,10 @@
 #define arch_mmap_check(addr, len, flags)       (0)
 #endif
 
+#ifndef arch_rebalance_pgtables
+#define arch_rebalance_pgtables(addr, len)              (addr)
+#endif
+
 static void unmap_region(struct mm_struct *mm,
                 struct vm_area_struct *vma, struct vm_area_struct *prev,
                 unsigned long start, unsigned long end);
@@ -241,7 +245,7 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
 
         down_write(&mm->mmap_sem);
 
-        if (brk < mm->end_code)
+        if (brk < mm->start_brk)
                 goto out;
 
         /*
@@ -1424,7 +1428,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
         if (addr & ~PAGE_MASK)
                 return -EINVAL;
 
-        return addr;
+        return arch_rebalance_pgtables(addr, len);
 }
 
 EXPORT_SYMBOL(get_unmapped_area);
@@ -2216,7 +2220,7 @@ int install_special_mapping(struct mm_struct *mm,
         vma->vm_start = addr;
         vma->vm_end = addr + len;
 
-        vma->vm_flags = vm_flags | mm->def_flags;
+        vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 
         vma->vm_ops = &special_mapping_vmops;